Solid-state laser instruments for producing high laser powers (for example, several 100 W to kW) usually include an optical space and a supply unit. The optical space contains the pumping light sources, the laser resonator, beam guide components, and coupling units for coupling the laser beam into one or a plurality of laser light cables. The supply unit contains the components that are necessary for the electrical supply, for the gas and the water supply, and for control of the laser, laser components, and associated units. The optical space is usually designed as a unit that is separated from the environment by a hood of the laser instrument. The hood ensures that no laser radiation is delivered to the environment in an uncontrolled manner. The hood is therefore provided with a safety switch that causes the laser resonator to be turned off when the hood is opened.
In most cases, high-power laser instruments have a plurality of exits for the laser radiation, i.e., a plurality of coupling units for connecting laser light cables. The laser beam can thus be distributed among a plurality of workstations via beam switching arrangements or splitters that are located in the laser instrument. The coupling units for connecting the laser light cables are located in the optical space of the laser instrument. The connected laser light cables are passed out through light- and air-tight lead-throughs in the hood of the optical space.
A laser light cable should be replaced if it ages or if it sustains damage. A replacement may also be necessary if a laser light cable of a different length is required at an exit. The hood of the optical space of the laser instruments commonly is opened to plug in or unplug a laser light cable at a coupling unit. Typically, the laser is automatically turned off in this case. Moreover, the optical space is completely open with respect to the ambient air, so that dirt and dust can reach the optical components unimpeded. The laser light cable plugs of known laser instruments already have safety elements in the form of electrical contacts which, in the plugged-in state, contact corresponding connections in the socket of the coupling unit and thus close an electrical safety circuit. When the plug is withdrawn, this contact is interrupted and the laser is turned off, so that the user is not in any danger due to emerging laser radiation. However, because of the reaction time of the safety circuit, it is still possible for the laser light cable to sustain damage due to emerging radiation at the instant when the plug is withdrawn. In addition, it is inconvenient and time-consuming to shut off and then restart the laser.